As an exercise physiologist, I believe understanding sports science can help you train smarter and achieve your best performances. As a professional coach and full-time runner, I understand that the scientific jargon can be like, well, scientific jargon. There's often a "disconnect" between what the physiologists say and what those in the real world of training and racing say (and do!).

In this article (the first of many offered on this website), I present a simple method to make the connection between science and reality and show you how to use this connection to improve your running. This way of looking at sports science gives you an idea of the underlying tenets of my philosophy of training. It would be presumptuous to say that this philosophy is a new, "magical" method. It's essentially just the simple process I've used to make sense of physiology and how it relates to the time-proven methods of great runners and coaches - who are our greatest teachers of how to train and race. The result is as close to a foolproof way to plan your training as I've found.

Graph 1: Making the Connection

The fundamental connection between the lab and your training/racing is illustrated in Graph 1, below. To fully understand this connection, let's simulate an exercise test and I'll describe how the variables measured relate to your training/racing.

Wired, Plugged and Ready to Run

If you come to an exercise physiology lab for testing, we'll have you run on a treadmill. We'll measure several variables that, as I'll show, are key indicators of how you should train to achieve optimal results and your fastest performances.

Once on the treadmill, we start you running at your slow, easy run pace. Our instruments measure your heart rate, ventilation/breathing rate, oxygen consumption (VO2) and the level of lactate in your blood. We also record your effort level at each speed. These variables are shown on the Y-axis of Graph 1, above. On the X-axis, your speed is charted, starting slow and gradually getting faster and faster. The X-axis shows race pace, described by time. In other words, one-hour race pace indicates that this pace is what you can race for one hour. You don't need to worry about what exact pace that is for you since the McMillan Calculator does it for you but I want to list these paces so you have an idea of the effort and how these match with changes in the physiological variables. Matching your real world speeds with various physiological variables is essential for applying the results of the test.

As you see on Graph 1, at your slow, easy pace, your effort is easy, heart rate and oxygen consumption are relatively low and your breathing is barely noticeable. There's also very little accumulation of lactate in your blood. This pace is what for years has been called "conversational pace".

The Aerobic Threshold or Second Wind

Once you're warmed up a little, we slowly increase the speed of the treadmill to around your two and half hour race pace - marathon pace for some runners, half-marathon pace for others, somewhere in between for most of us. Each of the variables on the graph gradually increases -- faster heart rate, ventilation, oxygen consumption, a little more effort and lactate. It's at this point (around two and half hour race pace) that runners often experience what has been called the "second wind". It seems that the systems of the body are geared up (muscles pliable with large delivery of blood, energy-delivery systems running efficiently) to the point where the pace seems to get a little easier. Some scientists have called this pace, your Aerobic Threshold. Again, you don't need to wonder what your two and a half hour race pace is, the McMillan Calculator calculates that for you.

Lactate, Anaerobic, Ventilatory Threshold

If we increase the pace to around your one hour and fifteen minute to two hour race pace, things begin to get interesting. Your effort becomes moderately hard but you could handle it for an hour or more. Both your heart rate and VO2 continue to increase at the same linear rate as before. At about this pace, however, you may notice that your breathing takes a noticeable increase - this is called the Ventilatory Threshold. The accumulation of metabolic by-products stimulates exhaling more air (and hence more CO2) to remove these products. We also see that lactate begins to accumulate slightly faster than at slower paces. In fact, if we increase the speed to around your one hour race pace, you see that your lactate curve takes a turn sharply upward. This is your Lactate Threshold, which you've probably heard about. Also present at this pace is what many call the Anaerobic Threshold. (This is differnet than the Aerobic Threshold discussed above.) The idea is that at the this threshold pace you begin to require increasingly more energy through anaerobic energy pathways.

Approaching Heart Rate and VO2 Max

Increasing the speed to 25 minute, then 15 minute race pace, your effort becomes harder and harder. Heart rate and VO2 continue their straight-line increase while your breathing is now labored. Lactate accumulates at a very rapid pace. The thighs become harder to lift. Fatigue sets in.

Reaching Your Anaerobic Capacity

When we take the pace even faster, reaching 10 then eight minute race pace, things really get interesting. Your effort becomes very hard, and breathing passes from tolerable to maximum capacity. Your heart rate and VO2 reach their maximum and stay there. Lactate is now accumulating very rapidly.

Redline City

If we finally kick the pace up to your five or four minute race pace (or faster), effort, breathing, heart rate and VO2 are all redlined and lactate floods the muscles and blood. It will only take a short time before you've had all your body and mind can take. You're now bathing in a sea of lactic acid. You give the STOP sign and straddle the treadmill belt until it slows to a walking pace.

Now the Fun Starts!

While you recover with an easy jog, allowing the fog that is total exhaustion to clear, we now have a clear picture of your physiological status across several speeds. We can link specific effort levels, heart rates, breathing rates, lactate levels and oxygen consumption values with these various running speeds and race paces at various distances. We've just made the key connection between the lab and the real world - physiological responses linked with specific race paces. Using this information, we can now prescribe very specifically, the optimal training paces you should use to affect various key aspects of your fitness: endurance, stamina, speed and sprinting.

I'm not suggesting that each runner needs to get a treadmill test performed. On the contrary, I find that Graph 1 is very similar for all high-performance runners so it's applicable to each runner's training. In other words, it's likely that at 30 minute race pace, you and other competitive runners will be operating at approximately the same percentage of max heart rate.

I simply wanted to help you understand the physiological reactions at various race paces so that you don't have to go to a lab for testing. I want to show that by being able to estimate your equivalent race paces for various race distances (which is what the McMillan Calculator does for you), you can then train very specifically to obtain the desired physiological adaptations.

Effectively, you've learned how to link sports science with multi-pace training, the training system that is the foundation of most of the world's successful training programs.

The Next Step

In the next section of this article, I'll take the results of this test one step further and show how the various energy systems of the body are linked to specific types of training. You're then ready to set up your scientifically-based, yet individualized program that gives you the best opportunity for success and removes all guesswork from your running.